In a digital recording scenario, the fluctuating voltage sent from the microphone is sent to an analog-to-digital convertor, or ADC. This device, perhaps housed in an audio interface box, takes “snapshots,” or samples, of the continuously changing amplitude levels at frequent, regular time intervals.
The number of amplitude levels to which a sample can be assigned is called the sample resolution. The rate at which samples are taken is called the sampling rate. The sampling rate for commercial compact disks (CDs) is 44,100 hertz (44.1 kHz). This means the ADC samples the signal from the microphone 44,100 times every second, each time assigning and storing in memory a particular amplitude level.
That’s a lot of amplitude records (or samples) in just one second!
The number of amplitude levels to which a sample can be assigned is called the sample resolution. The rate at which samples are taken is called the sampling rate. The sampling rate for commercial compact disks (CDs) is 44,100 hertz (44.1 kHz). This means the ADC samples the signal from the microphone 44,100 times every second, each time assigning and storing in memory a particular amplitude level.
That’s a lot of amplitude records (or samples) in just one second!
ACTIVITY: Calculate the frequency of a recorded tone. CLICK HERE FOR INSTRUCTIONS/HELP.
FOUR TONES - Recording of four instruments playing different, steady tones. You may use this to calculate their frequencies.
CLICK HERE for a table of frequencies for common musical notes.